Winning the Nobel Prize brings with it a diploma, cash award, and a 200 gram medal made of gold. Each medal is specially cast for the winner, emblazoned with his or her name.

Long after the award money is spent or donated, these precious gold medals survive as monuments to individual achievement. Most of the medals are displayed in museums and universities long after the winner's death, however, a few Nobel Prize recipients donated their gold medals for the benefit of others. Let's take a look at the stories behind Nobel Prize winners who handed over their medals to be melted down for the gold content, along with a feat of bravery involving four Nobel winners dissolving Nobel medals as Nazis ran through the streets of a city.

Melting down Nobel Prizes to aid war efforts
A handful of Nobel Prizes met an unusual end – fodder for the treasury of countries during World War I and II. Luigi Pirandellogave
his 1934 Nobel Prize in Literature to the Italian government, to be melted
down to aid Benito Mussolini
in funding the Second Italo-Abyssinian War.

Selma Lagerlöf, another winner of the Nobel Prize in Literature, donated her 1909 prize to the country of Finland in order to fund their efforts against a Russian invasion. Marie Curie donated a large amount of her savings to the French government during World War I, however, it is disputed as to whether the government accepted the offer to melt down their Nobel Prizes.

Hiding Nobel Prizes from Nazis
Two Nobel Prizes disappeared in order to prevent confiscation by members of the National Socialist Party during the invasion of Copenhagen. In 1940, the Institute of Theoretical Physics, led by Niels Bohr, played home to the Nobel Prize medals awarded to Max von Laue and James Franck.

Max von Laue held a professorship at the University of Berlin during this time, and staunchly opposed the National Socialist Party. James Franck spent this time in the United States, working in the Metallurgic Laboratory at the University of Chicago, one of the four Manhattan Project research centers. Von Laue ushered his medal out of Germany for safe keeping, as owning gold in Germany during WW II came with a severe penalty, while Franck sent his medal to Bohr's institute, a haven for Jewish scientists during the time.

Initially concerned for Max von Laue's safety, Bohr sought a manner to hide the medal. Bohr did not concern himself with his own Nobel Prize medal, as he auctioned the prize in 1940, with the proceeds aiding relief efforts in Finland. The auction winner donated the medal to the Danish Historical Museum, where it is displayed today.

A clever plan involving acid and trickery
Bohr charged future Nobel Prize winning chemist, George de Hevesy, with hiding the medals. George de Hevesy initially wanted to bury the medals, but Bohr declined believing the medals would easily be found, leading de Hevesy to dissolve the medals in a mixture of concentrated nitric and hydrochloric acid known as aqua regia.

Neither acid alone will suffice, but their combination allows for the gold atoms to enter into solution. Nitric acid creates a small supply of gold ions, and these positively charged ions react with negatively chloride ions from hydrochloric acid to form chloroaurate ions, pushing the equilibrium and dissolving more gold. George de Hevesy gives a personal account of his race against time to dissolve the Nobel prizes in his book, Adventures in Radioisotope Research.

In a feat combining courage and scientific acumen, de Hevesy spent an afternoon dissolving two extremely unreactive Nobel Prizes in beakers of agua regia as Nazis ran through the streets of Copenhagen. When the Nazis invaded Bohr's Institute of Theoretical Physics, the dissolved gold medals sat innocuously in the form of a yellow-tinged solution amongst a plethora of other chemicals and solutions.

Returning the Nobel Prize medals
Years later, an unknown scientist precipitated the gold out of the solution (possibly using Sodium Metabisulfite or Ferrous Sulphate). In 1950 Bohr delivered the gold that made up von Laue and Franck's prizes to the Royal Swedish Academy of Sciences in Stockholm.

In 1952, the Franck received a re-cast Nobel Prize medal in a ceremony at the University of Chicago. It is unknown how (or if) Max von Laue, suffering from deep depression and a general feeling of persecution at the time, received a re-cast version of his Nobel Prize medal.

The top image is of one of the Nobel Prize medals awarded in 1950 to researchers at the Mayo Clinic in Rochester, Minnesota. Tip of the hat to io9 reader Robbiecda as well. Additional image of the medal creation process courtesy of Myntverket (the Swedish Mint). Videos courtesy of Periodic Videos/Youtube and metalicmario/Youtube. Sources linked within the article.